Title :
Origin of the impedance cardiogram
Author :
Visser, Klaas R. ; Lamberts, Robert ; Zijlstra, Willem G.
Author_Institution :
Dept. of Physiol., Groningen Univ., Netherlands
Abstract :
The parallel conductor model for the thorax as used in impedance cardiography is extended to account for the influence on the thoracic heart-synchronous impedance variation of the packed cell volume and the shear-rate-dependent orientation of the erythrocytes in addition to the volume variation of the great intrathoracic blood vessels. The blood of four dogs was gradually replaced by a stroma-free hemoglobin solution, causing a decrease in resistivity as well as in resistivity variation of the blood, the latter due to variations in orientation of the erythrocytes. This was used to estimate the average value of the relative variations in the blood conductance at a packed cell volume of 40% to be 7.5%, 4.5% being caused by the variations in orientation of the erythrocytes and 3% being caused by the volume variations.<>
Keywords :
bioelectric phenomena; cardiology; dogs; erythrocytes; great intrathoracic blood vessels; impedance cardiogram; packed cell volume; parallel conductor model; shear-rate-dependent orientation; stroma-free hemoglobin solution; thoracic heart-synchronous impedance variation; thorax; volume variations;
Conference_Titel :
Engineering in Medicine and Biology Society, 1988. Proceedings of the Annual International Conference of the IEEE
Conference_Location :
New Orleans, LA, USA
Print_ISBN :
0-7803-0785-2
DOI :
10.1109/IEMBS.1988.95016
